Abstract:

Proton exchange membrane fuel cell (PEMFC) has attracted considerable interest because
of its superb performance, and many researches are focused on the development of highperformance,
long-life bipolar plates. Stainless steel bipolar plates offer many advantages
over the conventional graphite bipolar plates, such as low material and fabrication cost,
excellent mechanical behaviour and ease of mass production. However, the insufﬁcient
corrosion resistance and relatively high interfacial contact resistance (ICR) become the
major obstacles to the widespread use of stainless steel bipolar plates. In this work, active
screen plasma nitriding (ASPN), a novel plasma nitriding technique, was used to modify
thesurfaceof316austeniticstainlesssteel.Avarietyofanalyticaltechniques,includingXraydiffraction(XRD),scanningelectronmicroscopy(SEM),glowdischargeopticalemission
spectrometer (GDOES), were employed to characterize the nitrided samples. The results
reveal thatanitrogen supersaturated S-phase layerhasbeensuccessfully produced onthe
surface of all nitrided 316 stainless steel samples. The interfacial contact resistance (ICR)
valuecanbedecreaseddramaticallyafterASPNtreatmentandthecorrosionresistancecan
also been improved. In addition, better corrosion resistance can be achieved by active
screen plasma nitriding with a stainless steel screen than with a carbon steel screen. This
technique could beusedtoimprovetheperformanceand lifespan ofbipolar platesforfuel
cells.